Book Capter: Reference Module in Biomedical Sciences, 2025
https://doi.org/10.1016/B978-0-323-95488-4.00223-0
Arno C Gutleb, INVITROLIZE, Wellenstein, Luxembourg
Holger P Behrsing, Institute for In Vitro Sciences (IIVS), Gaithersburg, MD, United States
Sabina Burla, INVITROLIZE, Wellenstein, Luxembourg
Aline Chary and Tommaso Serchi, Luxembourg Institute of Science and Technology, Environmental Sustainability Assessment
and Circularity (SUSTAIN) Unit, Belvaux, Luxembourg
Andreas O Stucki, PETA Science Consortium International e.V., Stuttgart, Germany
Amanda Ulrey, Institute for In Vitro Sciences (IIVS), Gaithersburg, MD, United States
Cells may be exposed by submerged exposures (pipetting) or using one of various exposure systems allowing the exposure of cells cultured at the ALI to chemicals, (nano)particles, aerosols or gases. Although submerged exposures are less physiological than exposures to aerosols, they are relatively simple to perform without the need of special equipment. ALI exposure has reached a certain maturity and is currently widely recognized as the better alternative to submerged exposure in respiratory toxicology (Lacroix et al., 2018). However, the need to establish validated methods has been highlighted (Hiemstra et al., 2018).
For the exposure to gases or vapors the most frequently exposure principle is continuous flow. This method provides a continuous low flow of aerosol to the cell cultures with variable exposure duration (e.g., 20 min up to 48 h. A prerequisite is here sufficient availability of test material which can often be a limiting factor, proper dosimetry methods, and experience in Aerosol engineering.
Whenever cells are exposed to liquids or particle suspensions, the single droplet sedimentation principle can be used. The advantage of this method is that only small amounts of materials are required, deposition efficiency is high, and performing the exposure is relatively simple.
Dry powders can be exposed under continuous flow if they are available in amounts of several grams. For smallest quantities in the 1–100 milligram range special dry powder sedimentation systems are used – normally for scarce pharmaceuticals compounds or small samples from the environment.
